Configuration for cqi reporting in lte

ABSTRACT

A method and apparatus for receiving and processing channel quality index (CQI) reporting. A wireless transmit receive unit is configured to receive CQI configuration information and transmit a CQI report based on the CQI configuration information.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/341,383, filed Dec. 22, 2008; which claims the benefit of U.S.Provisional Application No. 61/018,505, filed Jan. 2, 2008 which isincorporated by reference as if fully set forth.

FIELD OF THE INVENTION

The present disclosure is related to wireless communication systems.

BACKGROUND

The Third Generation Partnership Project (3GPP) has initiated the LongTerm Evolution (LTE) program to bring new technology, new networkarchitectures, new configurations and new applications and services towireless networks in order to provide improved spectral efficiency andfaster user experiences.

In LTE, a wireless transmit receive unit (WTRU) may communicate with aneNodeB (eNB). The WTRU may send the eNB certain feedback to give the eNBan indication of the quality of the channel across which the WTRU andeNB are communicating. One particular type of feedback is a channelquality index (CQI) report (hereinafter “CQI”). CQI may be transmittedby the WTRU on a periodic basis or an aperiodic basis. A periodic CQImay be transmitted on the physical uplink control channel (PUCCH) or thephysical uplink shared channel (PUSCH). An aperiodic CQI may betransmitted only on the PUSCH.

Three different types of CQI's can be transmitted by a WTRU. A widebandtype CQI provides channel quality information of an entire systembandwidth of a cell. A multiband type CQI provides channel qualityinformation for a subset of system bandwidth of the cell. There is alsoa CQI for multiple input/multiple output (MIMO) type systems.

An LTE compliant WTRU may use PUCCH and PUSCH resources for transmittingCQI. The WTRU may send the CQI on the PUCCH as long as the WTRUmaintains synchronization. An eNB may configure the WTRU to transmitwideband or narrowband reports.

SUMMARY

A method and apparatus are disclosed for a WTRU to receive and processCQI reporting configuration information. The WTRU may be configured toreceive CQI configuration information and transmit a CQI report based onthe CQI configuration information. The configuration information may bereceived by the WTRU in a radio resource control (RRC) message. The WTRUmay receive information elements (IEs) that include specificconfiguration information.

BRIEF DESCRIPTION OF THE DRAWING

A more detailed understanding may be had from the following description,given by way of example and to be understood in conjunction with theaccompanying drawings wherein:

FIG. 1 shows an example wireless communication system including aplurality of wireless transmit/receive units (WTRUs) and an eNodeB inaccordance with one embodiment;

FIG. 2 is a functional block diagram of a WTRU and the eNodeB of FIG. 1in accordance with one embodiment;

FIG. 3 is a signal diagram of a random access channel (RACH) process inaccordance with one embodiment; and

FIG. 4 is a flow diagram of a method of CQI reporting in accordance withone embodiment.

DETAILED DESCRIPTION

When referred to hereafter, the terminology “wireless transmit/receiveunit (WTRU)” includes but is not limited to a user equipment (UE), amobile station, a fixed or mobile subscriber unit, a pager, a cellulartelephone, a personal digital assistant (PDA), a computer, or any othertype of user device capable of operating in a wireless environment. Whenreferred to hereafter, the terminology “base station” includes but isnot limited to a Node-B, a site controller, an access point (AP), or anyother type of interfacing device capable of operating in a wirelessenvironment.

FIG. 1 shows a wireless communication system 100 including a pluralityof WTRUs 110 and an eNodeB (eNB) 120. As shown in FIG. 1, the WTRUs 110are in communication with the eNB 120. Although three WTRUs 110 and oneeNB 120 are shown in FIG. 1, it should be noted that any combination ofwireless and wired devices may be included in the wireless communicationsystem 100.

FIG. 2 is a functional block diagram 200 of a WTRU 110 and the basestation 120 of the wireless communication system 100 of FIG. 1. As shownin FIG. 1, the WTRU 110 is in communication with the eNB 120. The WTRU110 is configured to receive instructions and parameters for feedbackreporting, including, for example, a CQI, from the eNB 120. The eNB 120may be configured to transmit, and the WTRU 110 configured to receiveand monitor signals on the broadcast channel (BCH). The WTRU 110 mayalso be configured to receive messages on the BCH, measure CQI, andtransmit CQI reports to the eNB (120). The WTRU 110 may transmit on anyuplink channel, such as a RACH, for example. The WTRU 110 may beconfigured to transmit and receive radio resource control (RRC) messagesand layer 1 (L1) messages.

In addition to the components that may be found in a typical WTRU, theWTRU 110 includes a processor 215, a receiver 216, a transmitter 217,and an antenna 218. The WTRU 110 may also include a user interface 221,which may include, but is not limited to, an LCD or LED screen, a touchscreen, a keyboard, a stylus, or any other typical input/output device.The WTRU 110 may also include memory 219, both volatile andnon-volatile, as well as interfaces 220 to other devices, such asuniversal serial bus (USB) ports, serial ports and the like. Thereceiver 216 and the transmitter 217 are in communication with theprocessor 215.

The antenna 218 is in communication with both the receiver 216 and thetransmitter 217 to facilitate the transmission and reception of wirelessdata.

In addition to the components that may be found in a typical eNB, theeNB 120 includes a processor 225, a receiver 226, a transmitter 227, andan antenna 228. The receiver 226 and the transmitter 227 are incommunication with the processor 225. The antenna 228 is incommunication with both the receiver 226 and the transmitter 227 tofacilitate the transmission and reception of wireless data.

When a WTRU begins communicating with an eNB, it may access a shareduplink channel, such as the random access channel. Accessing the RACH isa process that includes multiple messaging between a WTRU and an eNB.This is because the RACH is contentious, and many WTRUs may beattempting to use the RACH at the same time. FIG. 3 shows a RACH process300 in accordance with one embodiment. The RACH process 300 includes aWTRU (110 of FIG. 1) and an eNB (120 of FIG. 1) communicating four (4)messages to each other. Message 1 (302) is a RACH preamble transmittedby the WTRU. Message 2 (304) is the RACH response, transmitted by theeNB. Message 3 (306) is the RACH scheduled transmission, and message 4(308) is the contention resolution.

A CQI may be configured during the RACH process 300. The configurationinformation may be in RACH message 2 (304) or RACH message 4 (308). RACHmessage 4 (308) can include a relatively large amount of information ascompared to the other three messages (302, 304, 306). After the RACHprocess 300, the WTRU may be reconfigured for either periodic oraperiodic CQI reporting.

A WTRU may receive instructions and parameters to configure a CQI duringthe RACH process or in an RRC message after the RACH process. CQI reportconfiguration may include, for example, specification of the radioresource and type of CQI report.

A WTRU may require information as to where the CQI report configurationinformation may be found. The WTRU may receive a broadcast message froman eNB that may include an indication of where the WTRU may look for CQIreport configuration information. For example, a broadcast message mayinclude an indication that the WTRU should monitor the RACH to find CQIreport configuration information. Alternatively, the broadcast messagemay include an indication that that the WTRU should receive CQI reportconfiguration information in a radio resource control (RRC) message.

The CQI configuration indication may be found in a downlink channel suchas the primary broadcast channel (P-BCH) or the dynamic broadcastchannel (D-BCH). The indicator may be as small as one (1) bit. Forexample, a single bit value of 1 may indicate that the WTRU should usethe RACH, and a single bit value of 0 may indicate that the WTRU shoulduse RRC messaging. The location of this indication in the broadcastmessage may be specified in advance.

A CQI report may include, for example, a number indicating a CQIreporting process, a process ID and a set that includes the total numbersub-bands being measured. The set may be denoted as S. The set S may beconfigured by an eNB. The CQI computations by the WTRU may be done onthe set S.

The eNB my configure the CQI report type to be, for example, wideband orselected sub-band. The WTRU may receive an information element (IE) thatincludes periodic CQI report formatting information. For wideband CQIreporting, a single CQI report is transmitted that may be measuredacross all the sub-bands in a set S. For selected sub-band CQIreporting, a CQI report may be transmitted that is measured across asubset of set S. The sub-bands selected by the WTRU may be, for example,the sub-bands with the largest signal-to-noise ratio among the sub-bandsin set S. This type of CQI reporting is generally reported on the PUSCH.Alternatively, a MIMO type CQI report may include a CQI report for eachcodeword.

The CQI report may also include a CQI report type. The report type maybe represented by, for example, three (3) bits, when there are up to sixpossible report types. For example, 000 may represent widebandreporting, 001 may represent selected sub-band reporting, and 110 mayrepresent all sub-band reporting. If more than six (6) possible reporttypes are available, four (4) for more bits may be used.

For CQI transmitted by the WTRU on the PUCCH, the eNB may indicate ifthe WTRU is to use wideband CQI or frequency selective CQI. If usingfrequency selective CQI, the WTRU may select the sub-bands used formeasurement. The selection of the measured sub-bands may be an implicitfunction of a time index.

For CQI transmitted by the WTRU on the PUSCH, the eNB may signal one ofthree (3) possible CQI types that the WTRU may use. The eNB may signalthat the WTRU may use wideband CQI, selected sub-band CQI or eNBconfigured CQI.

If selected sub-band CQI is to be configured by the eNB, a compressedlabel scheme may be used. In this approach, a parameter M may beconfigured by the eNB, where M is an integer value. M may be smallerthan the total number of values the WTRU may use for CQI, and may beused to limit the number of values used by the WTRU for CQI.

If the eNB instructs the WTRU to use eNB configured CQI reporting, theeNB may indicate a differential compression method to be used by theWTRU. The reported CQI value may be a differential with respect to areference value, such as computing a wideband CQI differentially withrespect to neighbouring sub-bands, for example.

FIG. 4 is a flow diagram of a method of CQI reporting 400 in accordancewith one embodiment. At step 402 a WTRU may receive CQI positioninformation that includes where the CQI configuration information may befound by the WTRU. This position information may be transmitted on ashared downlink channel, such as a broadcast channel 404, for example.At step 406, the WTRU may receive the CQI configuration information.This may be located in an RRC message 408. At step 410, the WTRUprocesses the configuration information, measures for CQI and processesa CQI report. The format of the report may be based on the configurationinformation. At step 412, the WTRU may transmit the CQI report. The CQIreport may be transmitted in an RRC message 414, for example.

Resource allocation may implicitly indicate whether the PUCCH or thePUSCH will be used for CQI reporting. An uplink (UL) resource allocationfor CQI reporting may include time, frequency, code resource, duration,periodicity, and start time. The duration may be specified for periodicCQI reporting and the start time may be based on a system frame number(SFN). The resource allocation may be received by the WTRU in an IE. Ifa MIMO type CQI is requested by the eNB, the eNB may indicate theconfiguration information for each codeword to the WTRU.

CQI reporting may be reconfigured during operation of a WTRU. Thereconfiguration may include, for example, an eNB configuring and/orreconfiguring certain CQI reporting parameters or extending a CQI reportbefore it expires. In addition to using RRC for reconfiguration for CQIreporting, a medium access control (MAC) control protocol data unit(PDU) can also be used.

If the MAC control PDU is to be used for CQI reporting reconfiguration,then one (1) bit can be used in the MAC control PDU header to indicateif CQI reporting reconfiguration is included in the MAC control PDU.

If a specific MAC control PDU is used for CQI reporting, then indicationof the CQI reporting MAC control PDU may be placed at the beginning ofthe PDU and the number of bits used as an indicator may depend on howmany different MAC control PDUs exist. For example, if less than 32different MAC control PDUs exist, then five bits are enough to indicateif this is a CQI reporting reconfiguration.

The position of all information elements for CQI reportingreconfiguration in the MAC control PDU may be fixed prior to the WTRUstarting operation so that the WTRU knows what each element represents.

The configuration for aperiodic CQI reporting may transmitted by the eNBto the WTRU when a trigger is received by the eNB. The trigger foraperiodic CQI reporting from the eNB can be a one (1) bit indication.Alternatively, the request can be embedded into codewords in an uplinkgrant. The eNB may allocate the uplink grant for the WTRU so that theradio resource is available in an uplink shared channel. Theconfiguration message can be RRC, MAC, or layer 1 (L1) controlsignaling, for example.

The eNB may signal to a WTRU which CQI report type will be used foraperiodic CQI reporting. A single PUSCH sub-frame type report mayinclude a set of CQI values, each of which corresponds to a set ofsub-bands. The single PUSCH sub-frame type report may alternativelyinclude a sub-band specific CQI for all sub-bands or a CQI valueaveraged over multiple sub-bands.

For aperiodic CQI reporting, the eNB may configure the PUSCH resourcebased on the type of aperiodic CQI report. The control information sentby the eNB may include, for example, the radio frame, timeslot,frequency band, and possible code resource on the PUSCH for aperiodicCQI reporting.

Although the features and elements are described in particularcombinations, each feature or element can be used alone without theother features and elements or in various combinations with or withoutother features and elements. The methods or flow charts provided hereinmay be implemented in a computer program, software, or firmware tangiblyembodied in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) module.

What is claimed is:
 1. A method for configuring channel qualityreporting, the method comprising: a wireless transmit receive unit(WTRU) initiating a random access channel (RACH) procedure in order toestablish a connection with an eNodeB (eNB), wherein initiating the RACHprocedure comprises sending a first message comprising a random accesspreamble to the eNB; the WTRU receiving a second message comprising arandom access response from the eNB; the WTRU transmitting a thirdmessage comprising a scheduled transmission to the eNB; and the WTRUreceiving a fourth message from the eNB, the fourth message comprisingan indication for contention resolution and a channel quality indicator(CQI) reporting configuration, wherein the CQI reporting configurationconfigures the WTRU for at least one of aperiodic CQI reporting orperiodic CQI reporting.
 2. The method as in claim 1, wherein the RACHprocedure comprises the exchange of the first, second, third, and fourthmessages.
 3. The method as in claim 1, wherein the RACH procedure is acontention-based procedure.
 4. The method as in claim 1, wherein the CQIreporting configuration comprises an indication of a periodicity to beused for periodic CQI reporting.
 5. The method as in claim 1, whereinthe CQI reporting configuration is included in an information element(IE) of radio resource control (RRC) message.
 6. The method as in claim1, wherein the CQI reporting configuration comprises an aperiodic CQIreport type that is one of wideband, WTRU selected sub-band, or eNBconfigured sub-band.
 7. The method as in claim 1, further comprising theWTRU receiving a subsequent radio resource control (RRC) reconfigurationmessage that reconfigures that CQI reporting configuration.
 8. Awireless transmit receive unit (WTRU) comprising a processor configured,at least in part, to: initiate a random access channel (RACH) procedurein order to establish a connection with an eNodeB (eNB), whereininitiating the RACH procedure comprises sending a first messagecomprising a random access preamble to the eNB; receive a second messagecomprising a random access response from the eNB; send a third messagecomprising a scheduled transmission to the eNB; and receive a fourthmessage from the eNB, the fourth message comprising an indication forcontention resolution and a channel quality indicator (CQI) reportingconfiguration, wherein the CQI reporting configuration configures theWTRU for at least one of aperiodic CQI reporting or periodic CQIreporting.
 9. The WTRU as in claim 8, wherein the RACH procedurecomprises the exchange of the first, second, third, and fourth messages.10. The WTRU as in claim 8, wherein the RACH procedure is acontention-based procedure.
 11. The WTRU as in claim 8, wherein the CQIreporting configuration comprises an indication of a periodicity to beused for periodic CQI reporting.
 12. The WTRU as in claim 8, wherein theCQI reporting configuration is included in an information element (IE)of radio resource control (RRC) message.
 13. The WTRU as in claim 8,wherein the CQI reporting configuration comprises an aperiodic CQIreport type that is one of wideband, WTRU selected sub-band, or eNBconfigured sub-band.
 14. The WTRU as in claim 8, wherein the processoris further configured to receive a subsequent radio resource control(RRC) reconfiguration message that reconfigures that CQI reportingconfiguration.
 15. An eNodeB (eNB) comprising a processor configured, atleast in part, to: receive a first message comprising a random accesspreamble from a wireless transmit receive unit (WTRU), wherein therefirst message initiates a random access channel (RACH) procedure inorder to establish a connection between the WTRU and the eNB; send asecond message comprising a random access response to the WTRU; receivea third message comprising a scheduled transmission from the WTRU; andsend a fourth message to the WTRU, the fourth message comprising anindication for contention resolution and a channel quality indicator(CQI) reporting configuration, wherein the CQI reporting configurationconfigures the WTRU for at least one of aperiodic CQI reporting orperiodic CQI reporting.
 16. The eNB as in claim 15, wherein the RACHprocedure comprises the exchange of the first, second, third, and fourthmessages.
 17. The eNB as in claim 15, wherein the RACH procedure is acontention-based procedure.
 18. The eNB as in claim 15, wherein the CQIreporting configuration comprises an indication of a periodicity to beused for periodic CQI reporting.
 19. The eNB as in claim 15, wherein theCQI reporting configuration is included in an information element (IE)of radio resource control (RRC) message.
 20. The eNB as in claim 15,wherein the CQI reporting configuration comprises an aperiodic CQIreport type that is one of wideband, WTRU selected sub-band, or eNBconfigured sub-band.